Spill port control for free-piston units



3 Sheets-Sheet 1 INVENTQRS MM Mom" M' 4 Aug. 16, 1949.

Filed Jan. 30, 1 945 3 Sfieets-Sheet 2' Aug. 16, 1949. A. KALITINSKY EI'AL SPILL PORT CONTROL FOR FREE-PISTON UNITS Filed Jan. 30, 1945 nn lllllll FIG. 2

INVEDNTORVS (MW Mt" Z/% i W -1 1949- j A. KAL ITINSKY ETAL 7 SPILL PORT CONTROL FOR FREE-PISTON UNITS Filed Jan, '30, 1945 3 Sheets-Sheet 5 INVENTORS Patented Aug. 16, 1949 SPILL PORT CONTROL FOR FREE-PISTON UNITS Andrew Kalitinsky,

with, Hartford, Conn., assignors to Eagleville, and Walter A. Led- United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Application January 30, 1945, Serial No. 575,340

18 Claims.

This invention relates to a control for the spill port adjusting elements of free-piston units.

The copending Kalitinsky application, Serial No. 550,886, now Patent No. 2,441,273, dated May 11, 1948, shows a free-piston generator in which the eiiective volume of the compressor isadjusted by opening or closing one or more of a number of axially spaced rows of spill ports in the compressor cylinder. The ports are controlled by bands which are circumferentially movable on the periphery of the cylinder for opening and closing the ports. A feature of this invention is an actuating means for these bands by which the bard may be moved between open and closed position and held securely against movement at either position. Another feature is an actuating means that will be free from back lash.

It is advantageous to provide a positive actuation and locking, with no point at which the driven member is not positively controlled. A feature Of the invention is the arrangement of the actuating mechanism such that it remains positively engaged, after the motion of the driven member has ceased, until the locking structure has reached a position in which the driven mem- ,ber is positively locked.

In opening or closing successive rows of ports in sequence, it is essential that during the motion of any one closing member the remaining :nembers be held securely against movement of the position desired. A feature of this invention is an actuating device that will accomplish this result and will permit the closing means to be moved in the desired sequence.

Another feature of the invention is an actuating device which will permit reversal of the control means at any point in the operation without any lost motion. This feature is particularly desirable where the unit is adapted for automatic stroke control and utilizes the opening and closing of the ports for effecting the desired control.

Other objects and advantages will be apparent from the specification and claims, and from the accompanying drawings which illustrate an embo diment of the invention.

Fig. 1 is a sectional view through the free-piston unit.

Fig. 2 is a sectional view through the compressor cylinder showing the port closing means.

Fig. 3 is an enlarged sectional view showing the band actuating means on a large scale.

Fig. 4 is a sectional view on the line 4-4 of Fig. 3.

Fig. 5 is a view similar to Fig. 3 with the parts in different position. v

Fig. 6 is an end elevation showing the staggering of successive band actuating means.

The unit shown includes an engine cylinder I0 having reciprocating pistons l2 and M to which compressor pistons l5 and 18 in cylinders 20 and 22 are integrally connected. Sleeves 24 and 26 attached to the compressor pistons complete the reciprocating piston assemblies. The sleeves in combination with stationary pistons 28 and 30 form air spring cylinders.

The piston assemblies are moved apart by the burning of fuel injected into engine cylinder l0 through one or more nozzles 32. Air compressed in the air spring cylinders on the power stroke returns the piston assemblies. The assemblies are always maintained at equal distances from the center of the engine cylinder by a linkage, not shown.

Intake manifold 42, which extends around the compressor and engine cylinders conducts air to intake valves 44 in the heads of the compressor cylinders, through which air alternately enters opposite ends of the cylinders. The compressed air leaves the cylinders through discharge valves 46, also at opposite ends of the compressor cylinders and passes into a central scavenge chamber 48 and end chambers 50 and 52. These chambers may be interconnected by a scavenge manifold, not shown.

Compressed air from the scavenge chambers enters engine ports 54 and 56 which are uncovered by pistons l2 and I4 at the end of the power stroke, thereby permitting air to be blown through the engine cylinder. Gas and air in the engine cylinders is discharged through exhaust ports 58 into exhaust manifold 60.

Each compress-or cylinder has one or more axially spaced rows of spill ports 62 which may be adjusted to control the length of the effective stroke. Each row of ports may beindividually controlled by a band 64, Fig. 3, extending around th cylinder between projecting ribs 66 extending from the cylinder, and having spaced openings 68, Fig. 2, for alignment with the spill ports. Band 64 is relativelythin and is supported by a ring 10 extending around the cylinder outside of the band and having spaced openings 12 which are in line with the spill ports in the cylinder. Ring I0 may be held in position between the adjacent projecting ribs 66 by clamping wires 14 fitting in grooves 16 in the projecting ribs. Each ring I0 is enough larger in diameter than band 64 so that clearance is provided and the band is free to move between the outer periphery of the compressor cylinder and the surrounding ring;

Band 84 may have projecting lugs 18 on opposite ends fitting in notches 80 in a block -82. This block is guided for straight line movement by supporting lugs 84. Endwise movement of block 82 causes the band to be moved circumferentially for aligning the openings in the band with the ports in the cylinder. The band is actuated from a shaft 86 through an actuating and locking mechanism shown on a larger scale in Fig. 3.

Referring to Figs. 3 and 4 the block 32 has arcuate notches 88 and 90. As shown, these notches may be spaced apart axially an amount equal to the desired block movement and are engageable by cam surfaces 92 and 94 on the driving and locking member 96: This member 96, as shown, is splined to a sleeve 91 which, in turn, is splined to the shaft 86 to permit indexing,

Between the cam surfaces 92 and 94 is located the actuating pin 98 which during rotation of the member 96 engages with a slot I08 in the block 82 and moves the block laterally for shifting the spill port band. The pin 98 has an armate surface I82 which is concentric to the axis of rotation of member 96 and so arranged, as shown in Fig. 5 that, when the pin is tangent to one side wall of slot I08 at the upper corner, the opposite comer of the slot will lie in a continuation of the arcuate surface and clear the pin. Thus, at the point where pin 98 is about to disengage the slot (moving in a direction opposite to the arrow, Fig. 5) the arcuate surface will ride over the opposite upper corner. Similarly, the arcuate surface of the pin will ride over the corner of the slot in moving into a position in which the pin is tangent to the opposite wall of the slot, at the corner, before the pin begins to move the block. Adjacent to and communicating with the slot I 00 are arcuate surfaces or notches I04 and I86 with which the cooperating arcuate surface I02 on the pin 98 engages during the movement of the pin toward or away from the slot. The surfaces I04 and I06 have the same radius of curvature as the surface I02 on the pin, and extend from the corners of the slot I 00 in such a manner as to be engaged by pin 98 during its movement toward or away from the slot. The outer or upper ends of the surface I04 and I86 may be relieved, as shown, to permit easy engagement between the pin and these surfaces. It will be noted that notch 88 is concentric to notch I04, and notches 90 and I06 are also concentric to each other on block 82.

The relative positions of the ends of cams 92 and 94, each of which forms a part of a-cylinder, is such that when the pin 98 engages a. slot I00 to start motion of block 82 the end of the operative cam will be just withdrawing from the base of notch 88 or 98 to permit the block to move.

To insure against back lash or lostmotion between the band and the shaft 98, the arcuate surfaces I84 and I86 are so located that the pin I08 engages with these surfaces to prevent block 82 from moving during the part of the rotational movement of sleeve 86 during which either cam 92 or 94 is withdrawing from the base of the notch with which it engages. Thus, as shown in Fig. 5, which shOWS pin 98 in engagement with surfaces I02, the end I88 of cam 92 is approaching the base of notch 88 and moving in the di- I rection of the arrow and is about to reach a point at which the block 82 will be free to move to the right. At this time, the pin 98 engages with the arcuate slufaces I02 and prevents the block from moving until the pin is in the dotted line position shown and sets the block in motion.

after the block has moved to the right into a position in which pin 98 is leaving slot I00, the surface I06 engages notch I04 and prevents the block from moving to the left until the cam 94 has moved counterclockwise far enough securely to lock the block 82 against movement in either direction. As a result, the cams 92 and 94 hold the block 82 in positions in which the ports are either fully opened or fully closed, and the pin 98 moves the block for opening or closing the ports only when the block is released from the locking action of cams 92 and 94. The surfaces I82 and I84 in cooperation with the pin assist the cams in their locking action immediately prior to the actuation of the block by the pin.

Each compressor cylinder has a number of Similarly.

bands which are actuated in succession. Thus,

as shown in Fig. 6,

pin 98 for moving the band for the row of ports A, Fig. 1, is angularly spaced from pin 98 for the row of ports B and also angularly spaced from pin 98 for the row of ports C. Each band has an actuating member similar to the member 96, and the locking camson each member hold the associated band against movement except during the part of the rotation of shaft 86 during which the pin 98 is operative in moving the band. Thus, cm 92 and 94 for each locking member extend far enough around the circumference of the member to lock the bands during the major part of the shaft rotation.

It is to be understood that the invention is not limited to the specific embodiment herein illustrated and described, but may be used in other ways without departur from its spirit as defined by the following claims,

We claim:

1. In a free-piston unit, an engine cylinder, a compressor cylinder, and a piston assembly in said cylinder, at least one row of ports extending circumferentially around the compressor cylinder, and a band for opening and closing the row of ports, in combination with means for moving said band including a rotating element, and means on said element for moving said band between open and closed positions and for looking said band against movement in either of said positions.

2. In a free-piston unit, an engine cylinder, a compressor cylinder, and a piston assembly in said cylinder, at least one row of ports extending circumferentially around the compressor cylinder, and a band for opening and closing the row of ports, in combination with means for moving said band including a block connected to the band, an actuating member engaging with said block for moving the band, and locking means on said member for holding the block against movement when the actuating means are disengaged.

3. In 'a free-piston unit, an engine cylinder, a compressor cylinder, and a piston assembly in said cylinder, at least one row of ports extending circumferentially around the compressor cylinder, and a band for opening and closing the row of ports, in combination with means for moving said band including a block connected to the band having spaced arcuate locking notches and an intermediate narrow actuating slot, and a rotary actuating and locking member having arcuate peripheral surfaces engaging with the arcuate notches, and a. pin engaging with the narrow slot as the member is turned.

4. In a free-piston unit, an engine cylinder, a compressor cylinder, and a piston assembly in the associated notch at said cylinder, at least one row of ports extending circumferentially around 'the compressor cylinder, and a band for opening and closing the row of ports, in combination with means for moving said band including a block connected to the band, and having spaced arcuate locking notches and an intermediate narrow actuating slot. and a rotary actuating a d locking member having arcuate peripheral surfaces engaging with the arcuate notches, and a pin engaging with the narrow slot as the member is turned, said arcuate surfaces and pin being so arranged with respect to each other that the end of one of the peripheral surfaces reaches the base of the momentthat the pin engages the slot to move the block. I

5. In a free-piston unit, an engine cylinder, a

compressor cylinder, and a piston assembly in said cylinder, at least one row of ports extending circumferentially around the compressor cylinder, and a band for opening and closing the row of ports, in combination with means for moving said band including a block connected to the band, and having spaced arcuate lockingnotches and an intermediate narrow actuating slot, and a rotary actuating and locking member having arcuate peripheral surfaces engaging with the arcuate notches, and a pin engaging with the narrow slot as the member is turned, said block having additional arcuate notches connecting with the slot and engageable by the pin as it moves toward and away from the slot.

6. In a free-piston unit, an engine cylinder, compressor cylinder, and a piston assembly in said cylinder, at least one row of ports extending circumferentially around the compressor cylinder, and a band for opening and closing the row of ports, in com ination with means for moving said-band including a block connected to the band, and having spaced arcuate locking notches and an intermediate narrow actuating slot, and a rotary actuating and locking memberhaving arcuate peripheral surfaces engaging with the arcuate notches, and a pin engaging with the narrow slot as the member is turned, said block having additional arcuate notches connecting with the slot and engageable by the pin as it moves toward the slot, said pin having an arcuate surface on one side engaging with said additional notches.

7. In a free-piston unit, an engine cylinder, a compressor cylinder, 3, piston assembly in said cylinder, at least one row of ports extending circumferentially around the compressor cylinder, and a band for opening and closing the row of ports, in combination with means for moving said band including a block connected with the band and having an arcuate locking notch therein, said block also having an adjacent narrow actuating slot, and a rotary actuating and locking member having an arcuate peripheral surface engageable with the arcuate notch, said member also having an adjacent pin engageable with the narrow slot as the member is turned.

8. In a free-piston unit, an engine cylinder, a compressor cylinder, a'piston assembly in said cylinder, at least one row of ports extending circumferentially around the compressor cylinder, and a band for opening and closing the row of ports, in combination with means for moving said band including a block connected with the band and. having an arcuate locking notch therein, said block also having an adjacent narrow actuating slot, and a rotary actuating and looking member having an arcuate peripheral sur- 6 face engageable with the arcuate notch. said member also having an adjacent pin engageable with the narrow slot as the member is turned, said block having a notch adjacent to and connecting with the slot for engagement by the pin as it moves toward the slot.

9. In a free-piston unit, an engine cylinder, a compressor cylinder, and a piston assembly in said cylinder, at least one row of ports extending circumferentially around the compressor cylinder, and a band for opening and closing the row of ports. in combination with means for moving said band including. a block connected to the band, and having a linear movement, a rod having an angular movement, and means on said rod for causing movementof said block during a small part of the angular-movement oi the rod, and for locking said block against movement during the rest of the angular movement of the rod.

10. In a free-piston unit, an engine cylinder. a compressor cylinder, and a piston assembly in said cylinder, at least one row of ports extending circumferentially around the compressor cylinder, and a band for opening and closing the row of ports,,in combination with i'feans for moving said band including a block connected to the band, a rod having an angular movement, and means on said rod for causing movement of said block during a small part of the angular movement of the rod, and for locking said block against movement during the rest of the angular movement of the rod.

11. In a free-piston unit, an engine cylinder, a compressor cylinder, and'a piston assembly in said cylinder, at least one row of ports extending circumferentially around the compressor cylinder, and a band for opening and closing the row of ports, in combination with means for moving said band including a block connected to the band, and having a linear movement, a rod having an angular movement, and means on said rod for causing movement of said block during a small part of the angular movement of the rod, and for locking said block against movement during the rest of the angular movement of the rod, said means for movin and locking the block including a locking member having an arcuate peripheral surface, and an actuating pin, said block having an arcuate locking notch engaging the arcuate peripheral surface, and a narrow slot adapted toreceive the pin as the peripheral surface withdraws from the notch.

12. In a free-piston unit, an engine cylinder, a compressor cylinder, and a piston assembly in said cylinder, at least one row of ports extending circumferentially around the compressor cylinder, and a band for opening and closing the row of ports, in combination with means for moving said band including a block connected to the band, and having a linear movement, a rod hav ing an angular movement, and means on said rod for causing movement of said block during a small part of the angular movement of the rod, and for locking said block against movement during the rest of the angular movement of the rod, said means for moving and locking the block including a locking member having an arcuate peripheral surface, and an actuating pin, said block having an arcuate locking notch engaging the arcuate peripheral surface, and a narrow slot adapted to receive the pin as the peripheral surface withdraws from the notch, said block having an additional arcuate notch adjacent to and connecting with the slot for engagement by the pin as it approaches the slot.

13. A free-piston unit having an engine cylinder, a compressor cylinder, a piston assembly in said cylinders, a number of axially spaced rows of ports in said compressor cylinder, and a closure element for each row of ports, in combination with an operating member for actuating said closure elements in sequence for opening or closing the rows of ports, and cooperating means on said member for locking each of said closure elements against movement during the motion of the member except during the time that the closure member is being moved.

14. A free-piston unit having an engine cylinder, a compressor cylinder, a piston assembly in said cylinders, a number of axially spaced rows of ports in said compressor cylinder, and a movable band for opening or closing each of the rows of ports, in combination with an operating member for moving said bands in predetermined sequence, and cooperating means on said member for locking all of said bands against movement during the motion of said operating member, said locking means releasing each band during the time that the operating member is moving said band between open and closed positions.

15. In a free-piston unit, an engine cylinder, a compressor cylinder, and a piston assembly in said cylinder, at least one row of ports extending circumferentially around the compressor cyl.; inder, and a band for opening and closing the row of ports, in combination with means for moving said band including a block connected to the band, and having spaced arcuate locking notches and an intermediate narrow actuating slot, and a rotary actuating and locking member having arcuate peripheral surfaces engaging with the arcuate notches, and a, pin engaging with the narrow slot as the member is turned, said pin having an arcuate surface concentric to the axis of rotation of the locking member, and so arranged that when the pin is tangent to one side wall of the slot at the upper corner, the other upper corner of the slot will lie approximately in a continuation of the arcuate surface of the pin.

16. A free-piston unit having an engine cylinder, a compressor cylinder, a piston assembly in said cylinders, a, number of axially spaced rows of ports in said compressor cylinder, and a closure element for each row of ports, in combination with a, rotary shaft, and means on said shaft for moving said closure elements in sequence, said means including a block connected to each band, and an actuating and locking member cooperating with each block, the members for the several bands being angularly staggered on the shaft, each block having spaced arcuate locking notches and an intermediate actuating slot, each of said members having arcuate peripheral cam surfaces engaging with the notches, and a pin engaging with the slot as the member is turned, said pin having an arcuate surface concentric to the axis of rotation of the member, and to be free of one corner of the notch as the pin moves into engagement with the opposite side wall.

17. A locking and actuating mechanism including a block having a linear motion, and having at least one arcuate locking notch and an adjacent actuating slot, and a rotary actuating and locking member having at least one arcuate peripheral cam surface engaging the notch, and a pin engaging the slot, said pin having an arcuate surface concentric to the axis of rotation of the member and in a position such that when the pin is tangential to one side wall of the slot at the outer corner, the other corner will lie in a continuation of the arcuate surface.

18. A locking and actuating mechanism including a block having a linear motion, and having at least one arcuate locking notch and an ad jacent actuating slot, and a'rotary actuating and locking member having at least one arcuate peripheral cam surface engaging the notch, and a pin engaging the slot, said pin having an arcuate surface concentric to the axis of rotation of the member, said block having additional arcuate notches connecting with the upper corners of the slot and engageable by the arcuate surface of the pin as it moves toward or away from the slot.

ANDREW KALI'I'INSKY. WAL'Im A. LEDWITH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 877,492 Doelling Jan. 28, 1908 1,481,358 Dwyer Jan. 22, 1924 2,064,976 Janicke Dec. 22,1936 2,200,892 Pescara May 14, 1940 2,426,307 Kalitinsky Aug. 26, 1947 2,426,308 Kalitinsky Aug. 26, 1947 2,426,311 Ledwith Aug. 26, 1947 2,434,323 Ledwith Jan. 13, 1948 

